In the semiconductor industry, integrated circuits (ICs) are typically tested in wafer form prior to being packaged. That is, a wafer comprising a multitude of ICs is tested prior to dicing the wafer into individual chips. During this testing, the integrated circuits are individually tested on a wafer, and appropriate action is taken if the testing indicates that predetermined specifications are not met. After dicing, the individual chips are then packaged into a multitude of semiconductor packages, wherein the integrated circuits are electrically coupled to electrical contacts, such as for subsequent attachment to a printed circuit board (PCB). Once the chips are packaged, each semiconductor package is again tested, where again, appropriate action is taken if predetermined electrical specifications are not met.
Conventionally, manufactured semiconductor packages are tested in automatic test equipment (ATE), wherein the semiconductor package is inserted into a “contactor”, and wherein the electrical contacts of the semiconductor package contact and depress a plurality of spring-biased contactor pins, also called “pogo” pins. The contactor pins of the contactor generally provide a temporary electrical connection between the electrical contacts of the semiconductor package to a test PCB or test board. The test board, in conjunction with the contactor, is configured to electrically test the circuits of the circuit board prior to final assembly of the semiconductor package on a PCB.
One common problem with conventional contactors is that the contactor pins are generally considered a “wear item” of the contactor, wherein individual contactor pins may wear and/or become faulty due to wear, contamination, bending, or various other reasons. Faulty contactor pins, and thus faulty contactors, can result in continuity problems between the test board and the semiconductor package to be tested, as well as potential lost yield if the test apparatus is not monitored properly. Accordingly, in order to prevent such problems, the contactor pins are typically replaced throughout the operational life of the contactor.
FIG. 1, for example, illustrates a conventional method 10 for determining the repair and/or replacement of contactor pins in a contactor. The method 10 begins with inserting a complete set of new contactor pins into a test contactor in act 15. In act 20, a predetermined number of semiconductor packages are tested via the contactor, wherein upon reaching the predetermined number of packages tested, the entire set of contactor pins are removed from the contactor in act 25, and the method repeats itself by again inserting another complete set of contactor pins into the contactor again in act 15. Such a complete replacement of contactor pins is generally blind to whether any of the pins are actually defective, but rather, the predetermined number of tested packages is typically determined by estimates of when the pins should be replaced based on past experience. Clearly, such wholesale replacement can be disadvantageous, since it is likely that some, if not all, of the contactor pins may still have useful life, and the wholesale replacement thereof can have significant cost implications.
Conventionally, there is no off-line method or machine that allows automated diagnosis, measurement or verification of each contactor pin in the contactor. Accordingly, contactor pin performance over time has not been well understood, but rather, contactor pin replacement has been done either piecemeal by manual tests of the contactor pins, or by the wholesale replacement illustrated in FIG. 1, wherein repair of contactor pins and/or cleaning frequency has been typically based on fixed intervals and/or assumptions made concerning the condition of the pins.
Therefore, a need currently exists for an improved method for testing, validating, and monitoring devices such as contactors used in testing semiconductor devices. Accordingly, a reliable and cost-effective method for generally automatically characterizing a contactor device is desirable, wherein the contactor device can be not only readily tested such that actual data about the status of the contactor is achieved, but the subsequent use of the contactor device for testing semiconductor devices can be made more reliable to achieve improvements towards the goals of enhanced yields and device reliability. Furthermore, such a method should increase productivity of the contactor device, such that the problems associated with wholesale replacement of contactor pins and/or time-consuming manual testing of the contactor pins are ameliorated.